Buoyancy capsule for deep submerged buoys



Nov. 19, 1963 HOWELL ETAL 3,110,914

BUOYANCY CAPSULE FOR DEEP SUBMERGED BUOYS Filed Dec. 5, 1961 2 Sheets-Sheet 1 I: i 5* I if Fl G. l

INVENTORS.

HARVEY L. HOWELL ROBERT E. RUHFEL alumna A T TORNEX H. L. HOWELL ETAL. 3,110,914

BUOYANCY CAPSULE FOR DEEP SUBMERGED BUOYS Nov. 19, 1963 I 2 Sheets-Sheet 2 Filed Dec. 5, 1961 INVENTORS. HAQVEY L. HOWELL ROBERT E- RUHFEL A T TODNE Filed Dec. s, 1961, $91. No. 157,138 4 Claims. (Cl. a-s

It is frequently desired to set an instrument package at relatively deep depths in the ocean with the object of signal reception and transmission, condition sensing, and/or automatic data recording over long periods, and with unattended operation. In such a case, it is more feasible to have the instrument package placed in a floatation device, or underwater buoy, anchored to the ocean bottom by a length of cable and rising upward by positive buoyancy to a height deter-mined by the length of this cable. Lowering this package from the surface would frequently require a much longer cable, need constant attendance, and be subject to the uncertainties of surface weather conditions. These deep water buoys have generally been of two types. The first is in the nature of an underwater pontoon where positive buoyancy is provided by air inside a heavy metal shell rigid enough to withstand the great pressures existing at or near the ocean bottom. This requires a very large and heavy buoy with attendant difiiculties of transporting it to station by suitable surface vessels, use of heavy cranes to lift such devices from the vessels deck, etc.

A prior type of floatation platform for great depths has employed gasoline contained in a non-rigid vessel, namely, in a synthetic rubber bag. Positive buoyancy is obtained through the lower specific gravity of gasoline, as compared to that of water (said buoyancy being adjusted by the amount of gasoline put into the bag). This device has the serious disadvantage of high flammability, which leads to storage problems.

A further drawback of gasoline is that While it yields a favorable positive buoyancy in relation to the weight and vol-ume'of gasoline employed as compared to the weight and volume of the underwater pontoon, the weight and volume of gasoline precludes its use where a small, compact, deep water buoy having high buoyancy would be required.

On the other hand, the apparatus of this invention employs metallic lithium to provide positive floatation. The resulting combination of small size, light weight, high positive buoyancy, and adjustable means for varying buoyancy, has not heretofore been available. It should be noted that the feature of high positive buoyancy, high volume per weight ratio, is of the essence of the utility of the device. The buoyancy determines the free-rise time, permitting it to rise rapidly to the surface once released from its restraining table. This rapid rise facilitates location and recovery of the buoy.

Also, the magnitude of the positive buoyancy determines the weight of the instrument package that can be carried by a deep submerged buoy. Thus, a buoy with 50 lbs. of buoyancy can theoretically carry a package up to, but not equaling, 50 lbs. it will be appreciated that for various missions this buoyancy must be adjustable depending upon the Weight of the package. The predictability of lithium specific gravity is also a factor of some importance. Less than 2% density variation is estimated for production lots of cast sections, making buoyancy estimates quite accurate as compared with similar estimates for gasoline. A further advantage of the favorable size/weight ratio is that the small buoy in military applications presents a very small target to underwater object locating devices, such as sonar.

3,110,914 Patented Nov. 19, 1963 ICE It is a principal object of the present invention to provide a deep sub-merged buoy which incorporates a buoyancy capsule having extremely high positive buoyancy in relation to size and weight of said capsule.

A further object is to provide a buoyancy capsule wherein the amount of buoyancy can be readily adjusted.

Yet another object of the present invention is to provide a deep submenged buoy of strong, rigid construction adapted to withstand long term immersion in a deep sea environment and rough ship handling during launching and recovery.

Still a further object of the present invention is to provide a deep submerged buoy of hydrodynamic contour, enabling the device to surface with a minimum free rise ime upon release from its anchor.

It is a funther object of the present invention to provide receptacle means within said buoy for retaining an instrument package used in oceanographic data collection.

Yet a further object of the present invention is to provide a device having a pressure equalizing feature to proteot the thin rigid outer shell from the extremely high compression effects existing at [great depths of water.

These and other means and objects of the present invention will, in part, be pointed out with particularity and will, in part, be apparent from the following description and the accompanying drawing in which:

PEG. 1 is a perspective view of the buoy of this invention anchored in the ocean.

FIG. 2 is a section taken along line 2-2 of FIG. 1.

Referring more specifically to the drawing, there is shown in FIG. 1, a device of the present invention characterized generally by the numeral 15 restrained from floating to the surface of the body of water 11 in which it is submerged by the anchor line 13 attached to ring 33. As shown in FIG. 2, instrument retaining section 12 and buoyancy capsule section 14- together form a generally elongated cylindrical body, rounded, or otherwise tapered at each extremity, for hydrodynamic performance characteristics. That is, if the buoy were released at a deep depth, the buoyancy capsule would permit a free rise to the surface with minimum resistance from the ambient seawater 11 (FIG. 1). it will be appreciated that the novelty of the present device resides primarily in the buoyancy capsule; therefore, the instrument retaining section is not discussed in detail as it will vary with the given application. Thus, for purposes of illustration, instrument vessel 16 is mounted within retaining section 12. It is supported on an annular weblike structure characterized generally by the numeral 15. Structure 15 includes a hub 17, rim 19, and spokes 21. The rim 19 of supporting structure 15 is attached to fairing 20 (of the instrument retaining section 12) and then to the casing 22 (of buoyancy capsule section 14) by screw means 23. A lap joint fairs the connection between members l-Z and 1'4.

Casings 20 and 22 will generally be of light weight, nonferrous material, such as aluminum, or resin-impregnated Fiberglas. Casing .22 is connected to ring 35 by screw means 25.

Seawater is permitted to enter within the fairing 20 to surround the instrument package. Capsule section 14 is provided with a flexible diaphragm 26, said diaphragm being preferably formed of synthetic rubber and retained in position by ring 23 and seal 30 whereby the interior of capsule 14 is effectively sealed off by diaphragm 26. Within the interior of capsule 14 are disposed a plurality of lithium blocks 32 arranged in stacked array, and substantially filling the interior of this capsule.

As shown in FIG. 2, lithium block 32:: positioned at the rounded extremity of casing 14 is appropriately coutoured to fit the section; remaining blocks 32 are of substantially disc configuration and of diameter slightly less than the inner diameter of casing 22.

Lithium blocks 32 substantially fill the interior of casing 22. All of the remaining volume Within said casing is occupied by e. fluid such as mineral oil or kerosene 34 introduced into casing through opening created by removal of ring bolt 46 at top rounded end section 38. This fluid is chemically inert relative to lithium and to the Fiberglas casing and provides a protective bath for the blocks 32, 32a.

Since the specific gravity of lithium is 0.534, approximately one pound will displace two pounds of water, providing a positive buoyancy of one pound/ pound of lithium. Thus, for a device requiring 60 pounds of buoyancy, 180 pounds (3.7 cubic feet) of gasoline would be required as compared to 60 pounds (1.9 cubic feet) of lithium. These figures illustrate the very significant weight and size reductions which can be obtained in a buoy through the use of lithium for floatation.

in a typical application, the dimensions of the buoyancy capsule case are approximately 40" in length (and 11.5" in diameter, the thickness of the resin bonded Fiberglas casing being approximately The efiective buoyancy is arrived at as follows:

A further feature of the present invention is that of variable buoyancy whereby the positive buoyancy can be adjusted for specific applications. The individual lithium blocks are readily removable from buoyancy section 14, the volume occupied by said disc then being replaced by an equal volume of the fluid. Maximum buoyancy exists when all blocks are in position and minimum, when the entire area is replaced by a fluid medium, in this case, kerosene, which has a positive buoyancy little above that of the surrounding water. Highest positive buoyancy is necessary where a heavy instrument package is being carried by the unit whose weight must be overcome, or else where rapid free rise time is desired.

As shown in FIG. 2, the lithium blocks are inserted in casing 14, ring 28 and seal 30 added, retaining lugs 35 positioned. Section 12 is added to section 14- and screw means 23 secured to bring annular members against casings 2t and 22. A perforated aluminum back plate 39 protects diaphragm 26 which is clamped between plate 39 and ring 28. The housing is then filled with kerosene through norm-ally closed threaded port 36.

The very high buoyancy characteristic of lithium imparts a utility to the use of this material which far outweighs the need for specific precautions in handling this material. Relatively simple procedure is necessary. Lithium is shipped in containers surrounded by oil in order to protect the metal from the slow decomposition caused by air and from the reaction which results from contact with water. These containers can be stored on board ship quite safely below deck and transferred to the Fiberglas container at any time in preparation for the launching of the buoy. The metal can also be stored directly in the buoyancy capsule since the surrounding oil will perform the same function as the shipping container oil. Solid lithium may be handled by using rubber or plastic gloves or with metal tongs.

A major feature of the present invention is the employment of a diaphragm member 26 to enable a small lightweight unit to be positioned at relatively deep levels in the ocean. This diaphragm is preferably formed of synthetic rubber, and is of limited flexibility. Its function is to transmit the enormous stresses and pressures of ocean depth to the interior of the casing of the buoyancy capsule. This pressure can be withstood by the lithium blocks and practically incompressible liquid, oil or kerosene, in which the lithium discs are immersed. Since the combination of diaphragm incompressible liquid and solid lithium blocks equalizes the pressure against the casing exterior, the casing itself can be made of relatively thin lightweight material, such as Fiberglas. This material is preferred since, in addition to sturdiness and light Weight, it is chemically inert. It cannot corrode in seawater, nor will it set up electrochemical corrosion in neighboring metal parts.

In utilizing a device of the present invention, the buoy may be assembled on station by the transporting vessel, in accordance with the desired mission. The capsule is then connected to the instniment-retaining section by screw means 23. The device is then lowered into the sea by suitable hoist means attached to ring bolt 46. There has thus been provided by a device of the present invention, a compact lightweight buoy suitable for use at deep levels,and having very high positive buoyancy which buoyancy can be adjusted as desired over a relatively wide range.

Various changes and modifications can be made in the preferred embodiment of the present invention by those skilled in the art without, however, departing from the spirit of the invention as set forth in the following claims.

What is claimed is:

l. A deep-submerging buoy comprising:

an instrument-retaining section and a buoyancy capsule section, said buoyancy capsule having a casing of generally elongated cylindrical configuration provided with an opening communicating with the interior of said casing;

means for connecting said instrument-retaining section to said buoyancy capsule section;

metallic lithium disposed in stacked array within said capsule and being of diameter relatively close to, but less than the inner diameter of said capsule casing;

a liquid, chemically inert to said lithium and said casding of said capsule, disposed within said capsule; an

a flexible diaphragm member sealing said opening in said capsule, whereby said liquid and said lithium together substantially occupy the interior of said capsule.

2. A deep-submerging buoy comprising:

an instrument-retaining section and a buoyancy capsule section, said buoyancy capsule having a casing of generally elongated cylindrical configuration closed at one end and open at the other end;

means for detachably connecting said instrumentretaining section to said open end of said buoyancy capsule section;

sufficient metallic lithium disposed Within said cap sule to provide a desired magnitude of positive buoyancy when said buoy is submerged in water;

a liquid, chemically inert to said lithium and said casing of said capsule, disposed Within said capsule; and

a deformable diaphragm member sealing said open end of said capsule, whereby said liquid and said lithium together substantially occupy the interior of said capsule.

3. A buoyancy capsule for a deep submerging buoy,

said buoyancy capsule comprising:

a rigid casing of generally elongated cylindrical configuration provided with an opening communicating with the interior of said casing;

metallic lithium disposed within said casing;

a liquid, chemically inert to said lithium, and said casing, disposed within said casing and encapsulating said lithium; and

5 6 a resilient diaphragm member closing said opening References Cited in the file of this patent whereby said liquid and said lithium substantially UNITED STATES PATENTS occupy the interior of said capsule. 2 385 376 0 1 s t 25 1945 4. A device as in claim 3 wherein said casing for said :324 l j ee, 4: 1962 buoyancy capsule is formed of glass fibers, said resilient FOREIGN PATENTS diaphragm is formed of synthetic rubber, and said liquid is a hydrocarbon. 4 ,199 Great Britain May 17, 1934 

1. A DEEP-SUBMERGING BUOY COMPRISING: AN INSTRUMENT-RETAINING SECTION AND A BUOYANCY CAPSULE SECTION, SAID BUOOYANCY CAPSULE HAVING A CASING OF GENERALLY ELONGATED CYLINDRICAL CONFIGURATION PROVIDED WITH AN OPENING COMMUNICATING WITH THE INTERIOR OF SAID CASING; MEANS FOR CONNECTING SAID INSTRUMENT-RETAINING SECTION TO SAID BUOYANCY CAPSULE SECTION; METALLIC LITHIUM DISPOSED IN STACKED ARRAY WITHIN SAID CAPSULE AND BEING OF DIAMETER RELATIVELY CLOSE TO BUT LESS THAN THE INNER DIAMETER OF SAID CAPSULE CASING; A LIQUID, CHEMICALLY INERT TO SAID LITHIUM AND SAID CASING OF SAID CAPSULE, DISPOSED WITHIN SAID CAPSULE; AND A FLEXIBLE DIAPHRAGM MEMBER SEALING SAID OPENING IN SAID CAPSULE, WHEREBY SAID LIQUID AND SAID LITHIUM TOGETHER SUBSTANTIALLY OCCUPY THE INTERIOR OF SAID CAPSULE. 